Canterbury hooker Flynn started his rugby apprenticeship with their ITM Cup rivals Southland back in 2002. However, it was at Canterbury where he established himself on the New Zealand rugby scene. Playing in Super Rugby for the imperious Crusaders did Flynn the world of good and he earned a surprise call-up to the 2003 World Cup squad in place of Anton Oliver and made his debut for the All Blacks against Canada in Melbourne.

Finding himself behind Keven Mealamu and Andrew Hore in the All Blacks pecking order restricted Flynn's caps. But he has since played for the NZ Maori side and has continued to impress for the Crusaders. With this in mind, Graham Henry opted to take Flynn as New Zealand's third choice hooker for the 2011 World Cup.

The hooker made just a solitary replacement appearance against Tonga as New Zealand went on to claim the World Cup for the second time.